环境科学与生态学最新文献

Lead (Pb) has been used for centuries in currency, transportation, building materials, cookware, makeup, and medicine. Mining of Pb in the Roman era matched the ever-increasing demand for metallurgy, transportation, and industry, resulting in a marked deposition of human activity in the geologic record. Researchers use global snowpacks and ice cores to study the historic anthropogenic use of Pb and subsequent deposition into the environment. As the cryosphere resources erode with climate warming, there is an increased urgency to map the content and source of Pb distribution in the environment. In this systematic literature review, we examine studies of long-traveled background atmospheric lead signals in natural, undisturbed snowpacks and ice cores globally. After a systematic review of the literature, we have synthesized 165 published papers to contextualize current data availability and examine spatial and temporal coverage of existing long-range transported Pb records. Cumulatively, these papers contain 560 records for individual and transect sample sites. Of these site records, 147 are ice core analyses, 389 are from snowpits, and 24 span the snow to ice transition. The records are globally distributed, with a high concentration of records at the poles and fewer records at low latitude alpine sites. Long timescale records are available from the Greenland and Antarctic ice sheets (>100 000 years). Shorter timescale records are available for alpine glaciers (>15 000 years) and persistent snowpacks (generally <5 years). To illustrate the research potential of these records, we selected key global records to analyze and contextualize the Pb pollution record from the North Pacific, noting its unique record of China's industrial revolution and the subsequent explosion of industrial output from China over the last 45 years. Finally, we provide recommendations for future studies aimed at reducing current temporal and spatial gaps in the records. We suggest analyzing archived ice cores never before analyzed for Pb, focused proposals on regions with critical data gaps, continuous resampling of sites to include modern Pb emission sources, and use of analysis techniques which have low sample preparation requirements, high sensitivity, and capability for ultra-trace concentration Pb analysis.

While investigating fossil fuel alternatives, phase change materials (PCMs) are promising for thermal energy storage (TES) applications because of their high renewable energy storage density, constant phase transition temperature, affordable pricing, non-toxic nature, etc. However, several limitations, including liquid leakage, phase separation, supercooling, low thermal conductivity, and unalterable melting temperature, offer a challenge in their utilization. While numerous studies have addressed these issues, there is no universal solution for PCM challenges. Customized strategies are required to mitigate each drawback. This review paper provides a comprehensive summary of the mitigation techniques and enhancement methods employed and their influence on the thermophysical characteristics of these materials. Strategies to reduce supercooling involve incorporating nucleating agents, seeding, and microencapsulation. Eutectic PCMs with alterable melting temperatures can be designed to enable the use of a specific PCM in various applications. Shape-stabilized PCMs effectively prevent liquid leakage, which utilizes multiple support materials. Additionally, incorporating thickening agents to mitigate phase separation and enhanced heat transfer strategies through various methods, including nanomaterial additives, porous mediums, microencapsulation, and uniform heat transfer, are deeply discussed. The insights provided in this paper are valuable for selecting reliable PCMs and determining appropriate performance improvement methods to achieve optimal thermal performance in PCM-based TES systems. Furthermore, the article also proposes essential directions for the future advancement of PCMs.

The revised European Food Safety Authority (EFSA) guidance document for the risk assessment of plant protection products on honeybees requires an assessment of time-reinforced toxicity (TRT) using toxicokinetic-toxicodynamic modelling. While there are user-friendly software options available for this modelling, it is not specialised for this new application, therefore conducting the TRT assessment still requires additional manual calculations. Here we present TRTBee: a new, freely available tool which is capable of automatically performing all stages of the TRT assessment. The tool is based on robust and well-known algorithms. We conclude with a brief discussion of the open problems that still exist within the EFSA scheme.

Environmental Implications

The reported relative biological effectiveness (RBE) for thermal neutrons has a large range (5-51, for cytogenetic endpoints), which can confound radiation protection decision-making. To determine whether thermal neutron spectra can influence RBE, the RBE of reactor-derived thermal neutrons of average energy 31 meV was evaluated in human peripheral blood lymphocytes using two classical DNA double-strand break endpoints: the dicentric chromosome assay (DCA) and the cytokinesis-block micronucleus assay. Dose-response curves for 41 to 408 mGy revealed a preference for linear regression. Maximum RBE (RBEM) values of 6.7 ± 0.9 and 4.4 ± 0.7 were calculated for the DCA and the micronucleus assay, respectively. These 31 meV RBEM values were significantly lower than our prior results for 64 meV thermal neutrons, which yielded a DCA RBEM of 11.3 ± 1.6 and a micronucleus RBEM of 9.0 ± 1.1. Dose-specific RBE values decreased with increasing dose for both assays. Microdosimetry simulations demonstrated similar quality factor values for both thermal neutron spectra. Dose deposition differences on the cellular scale, the difference in dose rate between irradiation configurations, or a not-yet understood phenomenon may be responsible for the RBE difference between the 31 and 64 meV thermal spectra. These findings indicate that the currently accepted radiation weighting factor wR value of 2.5 for thermal neutrons may underestimate the radiation detriment to small or shallow tissue targets including the lens of the eye.